Relay computing mechanism



Jan. 13, 1948.. w. LANG 2,434,499

RELAY COIPUTING IECHANISM Filed .Nov. 10, 1944 5 Sheets-Sheet 1 roArelqys raBreldys Crelays WILL IAM LANG ATTORNEY Jan. 13, 1948. w, LANG 2,434,499

RELAY COMPUTING MECHANISM Filed Nov. 10, 1944 5 Sheets-Sheet 2 FIG. 1b.

' ILQQ INVENTOR W/LL/AM LANG AT'ToRNEY Jan. 13, 1948. w. LANG 2,434,499

RELAY COMPUTING MECHANI SM Filed Nov. 10, 1944 5 Sheets-Sheet 3 INVENTOR MLL/AM L-A/vc;

Jan. 13,-1948, v w. LANG 2,434,499

RELAY COMPUTING MECHANISM Filed Nov. 10, 1944 5 Sheets-Sheet 4 ATTORNEY MAG/757s s MAG/VH5 A Jim. 13, 1948. w. LAN 2,434,499

RELAY COMPUTING MECHANISM Filed Nov. 10, 1944 5 Sheets-Sheet s 34 e z a Q MAG/VH5 a MAGNETS c ATi'oRNEY Patented Jan. 13, 1948 UNITED STATES PATENT QFFICE RELAY COMPUTING MECHANISM William Lang, New- York, N. Y., assignor tolnternational Business Machines Corporation, New r N a o ti n. o N w'York Application November 10, 1944, Serial No. 562,755

Claims. 1

This invention relates to calculating machines of the record controlled type and more particularly to machines in which adding operations are performed electrically.

The principal object is to. provide an improved electrical relay accumulator for a calculating machine.

A more specific object is to provide novel con-v trolling devices for a relay accumulator whereby a. succession of amounts may be entered into an accumulator, each in the period required for two electrical impulses.

A more specific object is to provide mechanism for sensing a record card for amounts represented in decimal system of notation, convert the amounts into a combinational system of notae tion for accumulation in that system and convert the result back into the decimal system.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Figs. 1a, 1b, 1c and 1d placed in the order 1a 1b, 1c, 1d constitute a wiring diagram of the electric circuits of the apparatus.

Fig. 2 is a timing and sequence chart of the operations.

Fig. 3 is a timing chart of a modified sequence.

In the drawings the record card sensing devices are shown in a diagrammatic manner where in Fig. 1a, In represents a record card of the well known type, provided with rows and columns of index point positions in which digits are recorded by perforating selected positions. The vertical columns are divided into fields such as W, X, Y, and Z, show-n diagrammatically as twocolumn fields in which perforations are made to represent the numbers 46, 37, 52 and 96, whose sum 231 is to be obtained by the devices of the invention.

The record card i0 is placed in sensing position between a common conductive plate l2 and sets of brush sensing elements l4 of which there is one set for each card column. As usual, the presence of a. digit representing perforation in any card column will allow the related brush H to make electrical contact with conductive plate Before tracing circuits through the card perforations the sequencing commutator will be described together with the time chart in Fig. 2 Referring to Fig lb, after a card l0 has been placed in sensing; position, start contacts I6 are closed to energize clutch magnet ill by connecting it to opposite sides of current lines 20 and A continuously running motor M drives a clutch disk- 24. and when magnet is; is; energized it rocks its latching armature 26, torelease spring pressed dog 28 for engagement with constantly running clutch disk 24. As a result disk 30, upon which dog 28; is pivoted, will rotate for one revolution and similarly turn commutator 32 with which a row of brushes 34 coact. In Fig. 2, the develop: ment of commutator 32 is represented with brushes 34 indicated in their relative starting position.

Each brush 34 is wired to a pair or trio of relay magnets identified as R1, R2, R3, etc., and as commutator 32 revolves circuits are completed from negative line 2i! (Fig. 11);). to common brush 36. brushes 34'. their related r lay a ets t positive line 22.

As seen from Fig. 2, relay R14, is initially energized condition to hold circuits set up during a previous op ration. At the present time eneriz ti o o e ay R i o no f ct- Efi r amoun -.W h. c r i ens n position and commutator 32 rotating, it will be seen from Fig. 2 that relays R] and R5 both b c m ene i e R ior n t F re a R c o e ts of on oct fi a d R u n r y R6, olose ot o con c s R6 and 6- Closure of contacts Hit and Rlu will complete circuits through the perforations in the W field o t e a d o e r ize el ted relays o a on rou St a o a un t group Sur th pecific xam e, a ir t is. t ac ab from p sitive line 22, common plate l2, perforation in the 4. pos ion, r a up in gable 38, h 4 contact Hit, to the 4 wire of a group 46, the fo rth f om h left. of a gr up of wires 40,v t e smaenet. S1? o ne a ive in r n ly, t ore s a cir it. m line mote 12, e ol in the 6 position, the 6 brush l4, cable 42-, the 6 contact Riu, the 6 wire of a group 44, the sixth wire from the left of a group 48, to the 6 ma e 4 n egativ line 0- 'Ihus, the tens. and units digits 4 and 6 of the W amoun a se u on ma e S and 4- he c ntact of t ose ma n ts n ed ra ly Sta and S e conn c p ti 1 22 to combina o f ur Wires. 5 nd 52- rd.- anoe with the well known binary code. Thus, h 1 magne S con e ts ine 2 t he 1 Wir 2; magnet S onne s ne 22 to t e 2 w re 50, magnet St connects line 22, to the 1 and '3 wires 50, 4 magnet $1 connects line 22 to the 4 wire 50, 5 magnet St connects line 22 to the 1 and 4 wires 50, 6 magnet, St connects line 22 to the 2 and 4 wires 5,0,7 magnet St connects line 2 2 to the 1, 2 and 4 wires 50, 8 magnet'S t conmee s ine 22. to h 8 W r 50. a e Si conneots ne 2 to the 1 d 8 ir s 5.

o th amou 6; a ci c is acc ng traceab e o e ten di it. 4 rom l e. .2 (F lol'. i e 54 cont ts Ste of; th 4 mag et fit the 4 wire 50, contacts RBt (now closed) to the 4 wire of a group 56 (Fig. 10) to a magnet A4 and wire 58 to negative line 20. A parallel circuit is also traceable from line 22 (Fig, la) wire 54, the 2 and 4 contacts Sua of the 6 magnet Su, the 2 and 4 wires 52, contacts Rtu, the 2 and 4 Wires of a group 60 (Figs. 1c and 101), to magnets A2 and A4 and wire 62 to line 20.

The amount 46 is thus sensed, converted into binary code and entered on the A magnets A4 for the tens digit and A2, A4 for the units digit. These magnets close contacts sumxed a to provide holding circuits through relay magnet contacts R1311, R! St of which a representative one is traceable in Fig. 1d from positive line 22, contacts R1311, contact A4a, magnet A4, wire 62 to negative line 211'. This holding circuit holds the A magnets energized for the period indicated opposite Rl3 in Fig. 2.

Combine amounts in A and B magnets.The next step or portion of the cycle designated W+ in Fig. 2 serves to add the amounts set in the A and B magnets and enters the result in the set of C magnets. Since there is no setting in the B magnets the amount 45 will be transferred from the A set to the C set and this is effected by the energization of magnets R8, R9 and RIB, during this step of operation.

In Figs. 1c and 1d the A and B magnets control sets of contacts suffixed b, electrically interconnected to form an adding chain that may be termed the A, B adding chain and which connects line 22 to the wire of a group designated 64 for the units order and 66 for the tens order, corresponding to the units digit of the sum of the digit set on the A and B sets of magnets in each order.

Specifically, for the example of an entry of 6 on the A magnets of the units order, Fig. 111 (i. e., magnets A2 and A4 energized), upon closure of contact Rlfiu (Fig. 1d), a circuit is traceable from line 22, contacts R1611, right hand contacts B81), right hand contacts A8b, right hand contacts B4b, right hand contact A45 (shifted), contacts 1321), third from the left, contact AZb, third from the left (shifted), contacts Blb, second from the left, contacts Alb, fourth from the left, 6 wire 64 (Figs. 1c and 1a), contacts R911 (now closed), 6 wire 44, 6 wire 48 and 6 magnet Su to negative line 20. In this manner, upon energization of magnets R9 and R16 the units digit of the sum of the digits in the units order is entered on the Su magnets.

Concurrently, the energization of magnets R9 and R16 will energize the St magnet corresponding to the units digit of the sum of the A and B settings in the tens order; (4+0=4). This circuit is traceable from line 22 (Fig. 10), contacts Rl6t, right hand contacts B812, right hand contacts A85, right hand contacts B411, right hand contacts A4b (shifted), contacts B212, third from the left, contacts A212, third from the left, contacts Bib, third from the left, contacts BCb, sixth from the left, contacts Alb, sixth from the let 4 Wire 66 (Fig. 1a) contacts R971 4 wire 45, 4 wire 45 and 4 magnet St to negative line 2i]. Magnets St and Su are thus set to represent 46.

Inspection of the adding chain in Fig. 1d, for example, through the 11 contacts of the A and B magnets will show that for all combinations of A and B digits the circuit will extend from line 22 to the wire 64, representing the units digit of the sum of the two digits set up and the following table will assist in tracing the several combinations. In a column headed Carry wire is indicated a wire through which a carry circuit is completed Where the sum is greater than 9. A specific circuit showing this will be traced following the table.

- A Mag B Mag- Carry A Digit nets B Digit nets Wire 64 Wire 1 1 0 1 1 1 1 l 2 1 1 2 2 3 1 1 3 1,2 4 1 1 4 4 6 1 1 5 1,4 6 1 1 6 2,4 7 1 1 7 1, 2,4 8 1 1 8 8 9 1 1 9 1,8 68 2 2 0 2 2 2 1 1 3 .1 2 2 2 2 4 i. 2 2 3 1,2 5 2 2 4 4 6 2 2 5 1,4 7 2 2 6 2,4 8 2 2 7 1,2,4 9 2 2 8 8 70 2 2 9 1,8 1 70 3 1,2 0 3 3 1,2 1 1 4 3 1,2 2 2 5 3 1,2 3 1,2 6 3 1, 2 4 4 7 3 1,2 5 1,4 8 3 1,2 6 2,4 9 3 1.2 7 1,2,4 68 3 1,2 8 8 1 70 3 1,2 9 1,8 2 70 4 4 0 4 4 4 1 1 5 4 4 2 2 6 4 4 3 1,2 7 4 4 4 4 8 4 4 5 1,4 9 4 4 6 2.4 4 4 7 1,2,4 1 4 4 8 8 2 4 4 9 1,8 3 5 1,4 0 5 5 1,4 1 1 6 5 1,4 2 2 7 5 1.4 3 1,2 8 5 1,4 4 4 9 5 1,4 5 1,4 5 1,4 6 2.4 1 5 1,4 7 1,2,4 2 5 1,4 8 8 3 5 1,4 9 1,8 4 6 2.4 0 6 6 2,4 1 1 7 6 2,4 2 2 8 6 2.4 3 1,2 9 6 2,4 4 4 70 6 2,4 5 1,4 1 70 6 2,4 6 2,4 2 72 6 2,4 7 1,2,4 3 72 6 2,4 8 8 4 74 6 2,4 9 1,8 5 74 7 1,2,4 0 7 7 1,2,4 1 1 8 7 1,2,4 2 2 9 7 1,2,4 3 1,2 68 7 1,2,4 4 4 1 70 7 1,2,4 5 1,4 2 70 7 1,2,4 6 2,4 3 72 7 1, 2,4 7 1, 2,4 4 72 7 1,2,4 8 8 5 74 7 1, 2,4 9 1,8 6 74 8 8 0 8 8 8 1 1 9 8 8 2 2 72 8 8 3 1,2 1 72 8 8 4 4 2 74 8 8 5 1,4 3 74 8 8 6 2,4 4 74 8 8 7 1,2,4 5 74 8 8 8 8 6 76 8 8 9 1,8 7 76 9 1,8 0 9 9 1,8 1 1 4. 68 9 1,8 2 2 1 72 9 1,8 3 1,2 2 72 9 1,8 4 4 3 74 9 1,8 5 1,4 4 74 9 1,8 6 2,4 5 74 9 1,8 7 1,2,4 6 74 9 1,8 8 8 7 76 9 1 9 1,8 8 76 O O 0 1 1 1 0 2 2 2 0 3 1,2 3 0 4 4 4 0 5 1,4 5 O 6 2,4 6 0 7 1, 2,4 7 0 8 8 8 0 9 1,8. 9

-Assume, for example, a setting in the units near 618 9 on the A m'agnets and a settirig of 2 on the B magnets. Thecarry'eircuitwould th'n b'e' trao'able from line 22, contacts 'RlGu, contactsBBb, right ha'nd contacts Kflb (shifted) left hand contacts 3%, left hand conta'cts A412, left hand contacts B2b (shifted), wire 12, cable 58 (Fig 1c), to one coil of a multiplecoil inagnet BC, 'wire 58 to negative line 20. This circuit branches-after 'nass'ing through'left hand contacts Bi-b (shifted) to the right hand "contacts Bib *(shifted), contacts A Zb (second fr'or'n th'e right), right hand contacts Blb, contacts Alb (shifted, second from the right), the ---1 wire 64 (Figs. 1c andla), contacts Him to the 1 wire 44 and wire 46 't'othe 1 relay Su and line 20. 4

The adding chain for the A and B-settings in the tens order (Fig. 1c) is just thesanieas for the iiiiits order except that the contacts BCb are inte'r'p'osed to add a unit "to the sum in the tens "orderwhen there is a carry from the units order. In the'tehs adding chain there are in turn 'carr; circuits branching through wires 68a, 10a, 12a, Rfia and 16a, corresponding to wires 68 to 16 for the'units order and thesetogether withan added wire i Bb'runthrough cable 18a (Fig. 1b) to the coils of -magnetBC in the hundreds order to shift cohtacts'BCb in that orderwhen there is a tens c'a'r'ryfromthe tens order.

"ifis e'x plai'ned, the sum of'the A and B settings is-now entered inthe St andSu magnets-and with "magnet R8'also energized at'this time (see Fig. 2) circuits extend from'line 22 (Fig. la), wire 54, cbnta'cts Sta,'-wires 50, contactsR St, wires '80 (Fig. ie) to-the C magnetsin the tens order,"corre'- spending to the digit set-on the St magnets, and

wire 58 to line 20.

Concurrently, circuits 'extend'from line 22 (Fig. Ta) Wire'54, contacts Sua, wires 52, contactsRSu,

Wires (Figs. 1c and 1d) 'to'the C magnets inthe'nnitsorder corresponding to the digit set on theSu magnets, and Wire 62 to line 20. For the example chosen the Cmagnets are now energized *torepresent 4'6. They'close their contacts Cia, 62a, 04a and GM as the case may be to provide holding circuits "completed wheninagnet RIB is energized, trac'eablein the units order, from line "22 (Fig. 1d), contacts'Rl5u, contacts Cla to 0841, magnets CI to C8,'wire 62 to line 2!). The C magnets will thus be held-for the period indiated in Fig. 2 after the holding circuits for the "A -and -B magnets are broken by dee'nergi'zation of magnets'R l 3 and R I 4.

'Enter amount X.When magnets R2 and' RG now close the second field of the card Ill (Fig. la) will be sensed and the amount 31 therein, entered *into the S magnets through circuits traceable from line 22, common plate l2, perforations in the 3 and 7 positions, related cables '38 and 42, contacts R21, and R2u, wires 46 and 44,'wires 4t! -an'd'48 to magnets St and Su and line 20. These magnets (the Smagnet St and the '7 magnet Su) -'c1ose their contacts Sta and Sua to complete circuits to magnets Al and A2 in the tens order and magnets Al, A2 and A4 in the units order. These circuits are traceable from line 22 (Fig. 1a), wire '54, contacts Sta and Sua, wires 50 and 52, contacts 'RGtand R611, wires 56-and 60 (Figs. 1c and id) to the A magnets in the tens and units orders, "wires '58 and62 to line 20. Thereafter, when magnet Rl3 is energized the A holding circuits Pare-established for the period indicated.

;'Ihus,'as seen from "Fig.- 2, when magnets'R2 :and R6 have deenrgized' only magnets A and C -are:he1d when magnets R1, RH.) and RH now "75 and the A and C magnetsto *be ntere'd into' the B magnets whose setting' -will then retirsent'the sum of amounts W- and X or-'83.

Referring to Fig. 1d the contacts suffiired "c of the A and C ina'gnets-ar'e interconnected to form an adding chain that isexactly similar to the A and B adding chain'so that when 'co'ntaot's RiI-Tu close acircuit is completed from line 22, through the-chain to the-3 :wire"'84, traceable'specifically from contacts "Rt I'll, contacts *CBc, right hand contacts "A8'c, right hand contacts C40 (shifted) center contacts A' ic (shifted), left handcont'acts C20 (shifted) ,right'hand contactsC2e (shifted), contacts A20, fifth from thele'ft sl'iifted),-contacts Clc, fourth from the left, contacts Ale,

eighth from the left (shifted), to the '3 'wire '8'4 which extends (Figs. 1c and 1a.) to contacts RHlu 'magnet'su to 1in'e20.

A carry circuit branches'at contactsCZc (Fig.

id) -through-wire 92, cable'98 (Fig. -10) to acoil of -multiple magnet Cc,'wire58 to line 20. Magfrom the left (shifted), 8 wire I00 (Fig. 12:).

contacts R'lUt,'-8"wire '46,"8"wire 40 to the 8 ma net St.

With magnets "Rf! energized circuits'cont'i'nue from 1in'e'22 (Fig. 'la), Wire'BL-conta'cts Staan'd Sua, wires 50 and 52, contacts R and RM, wires I02 and H34 (Figs. 1c and 1d) 'totherna'g'nets B in'the tensan'dunitsorders 'and wires 5'8 and' GZ to line'20. I

Thus, the-surn 83 is set on the 1B magnetsand when magnet RM 15 now energized contacts RMu and RMt provide circuit paths to hold the -B magnets after the A and C-maghets become deenergized.

"Enter amount Y.'This step 'of the operation is a repetition of the -step "in which the 'W amount was entered, the only difierence being in the r energi'zation of magnet instead of R l whereby contacts R3t andR3u will direct-the circuit tothe St and Su'magnets to set up the -amount52 therein andthese magnets in'turn, through their contacts Sta and Sua and contacts RBt-and Rii'u, will set up the amount 52 in the A magnetsfiand thereafter magnet R f3 is energized to provide a holding circuit. Thus, just after the per-ion headed enter Y-in-Fig.' 2, the magnets Al and A4 and'BB'inthe tens order and the magnets A2,

"BI andBZ in theunits order will be in-energized condition.

complete a circuit to the 3 wire 56 and ultimately to the CI- and C2 magnets of the te'nsorder. tens carry circuit branches through wire Na (Fig. 10) "and cable 18a -(Fig 1-b) to enefgizea coil of magnet-Bo in the-hundredsforder so that 7 in this order there is a circuit traceable from line 22, contacts Rlfih, contacts 132b, Blb, right hand contacts BCb (shifted), 1 wire I06 to the magnet Cl and line 20. Thus, the C magnets are now set to represent the sum of W, X and Y or 135 and the next step follows.

Enter amount Z.-This step is a repetition of the step wherein amount X was entered. Through the now familiar circuits the Z amount 96 is entered on the S magnets and then on the A magnets and held. In the adding part of the period the Al, A8, CI and C2 magnets are set in the tens order, the A2, A4, Cl and C4 magnets are set in the units order and the CI magnet is set in the hundreds order.

Consequently, when magnets R1, RH) and RH now become energized the sum 231 becomes set on the B magnets which are held as the commutator 32 completes its revolution. Briefly, tracing the circuits involved for the units order, the A plus C adding chain directs the circuit through the 1 wire 85 and carry wire 90 to energize the B! magnet of the units order and the Cc magnet of the tens order.

In the tens order the A plus C adding chain directs the circuit through the 3 wire I and carry wire 92a to energize the BI and B2 magnets of the tens order and the C0 magnet of the hundreds order.

In the hundreds order the right hand adding chain completes a circuit from line 22, contacts Rllh, C20, Cic (shifted) center contacts 000 (shifted), 2 wire A08 and magnet B2 to line 23. Accordingly, at the end of the cycle the B magnets alone are set to the total and held.

Another record card may now be placed in sensing position and another revolution of commutator initiated to progressively increase the total.

When it is desired to obtain an indication of the total standing in the B magnets at the end of any cycle, total key T is closed. This causes energization of magnets R12 and RIB and will complete a circuit through the A plus B adding chains to light lamps Lu, Li and Lh, in the several orders in accordance with the digital value set in the orders. The total circuit for the units order would be traceable from line 22 (Fig. 1d) contacts Pti2u, B82), right hand contacts A8b, right hand contacts 13%, right hand contacts A413, contacts B212, second from the right, contacts A21), second from the right, right hand contacts Bi b (shifted), contacts Alb, third from the right, 1 wire 64, cable Hi], 1 contact RlQu and 1 lamp Lu to line 28. The circuits in the tens and hundreds orders are similarly traceable.

The foregoing, accordingly, describes an apparatus in which successive entries may be made and in which each entry is effected by a pair of electrical impulses. Thus, the impulse indicated in Fig, 2 under enter W enters W in the A magnets and the following pulse under W+0 effects summation and entry into the C magnets. The next entry results in the sum appearing in the B magnets and so on with each progressive total being set in an alternate one of the B or C set of magnets.

Fig. 3 shows a modification of the section of the commutator whereby the record card would have the amount in its W field read and entered twice and then the amount in the X field read and entered twice to obtain 2W+2X, and the Y and Z fields would not be read. Other combinations of sequence in which the amounts may be read will occur to those skilled in the art and where amounts are to be subtracted the fields may obviously be perforated in accordance with the tens complement of the number.

The entire apparatus may be cleared by disconnecting either line 20 or 2! from the source of current whereupon all relay magnets will become deenergized.

While there have been shown and described and pointed out the fundamental novel features of the invention, it will be understood that various omissions and substitutions and changes in the form and details or the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In an electrical computing apparatus, a set of relay magnets, means for repeatedly setting said magnets to represent a succession of amounts to be added, a second set of relay magnets settable to represent amounts, a third set of relay magnets settable to represent amounts, means jointly controlled by the first and second set of magnets and rendered effective upon the first and alternate entries into said first set, for entering the sum of the amounts set in said first and second sets, into the third set, means jointly controlled by the first and third set of magnets and rendered effective upon the second and alternate entries into said first set, for entering the sum of the amounts set in said first and third sets, into the second set, and means for clearing each of said pair of sets of magnets subsequent to the entry of its sum into the remaining set of magnets.

2. In an electrical computing apparatus, a first, second andgthird set of relay magnets, each settable to represent an amount, means for entering a first and second amount into the first set of relay magnets in succession, computing devices controlled by the magnets of the first and second sets, and effective upon entry of the first amount for obtaining the sum of the amounts set in said first and second sets of magnets, and entering said sum into the magnets of the third set, further computing devices controlled by the magnets of the first and third set and eifective upon entry of the second amount, for obtaining the sum of the amounts set in said first and third sets of magnets and entering said sum into the magnets of the second set, and means for clearing each of said pair of sets of magnets subsequent to the entry of its sum into the remaining set of magnets, whereby successive sums will be alternately represented on the second and third sets of relay magnets.

3. In an electrical computing apparatus, a first set of relay magnets settable to represent an amount, a set of contacts adjusted thereby, a second set of relay magnets settable to represent an amount, a set of contacts adjusted thereby, a third set of relay magnets settable to represent an amount, a set of contacts adjusted thereby, circuit connections interconnecting the contacts of the second set and part of the contacts of the first set in accordance with the table of addition to form a first adding chain, circuit connections interconnecting the contacts of the third set and another part of the contacts of the first set in accordance with the table of addition to form a second adding chain, means for repeatedly energizing the magnets of the first set to represent thereon a succession of amounts, means efiec- 9 tive upon setting the first and alternate amounts on said first set of magnets for rendering the first adding chain effective and causing it to control the magnets of the third set, and means effective upon setting the second alternate amounts on said first set of magnets for rendering the second adding chain efiective and causing it to control the magnets of the second set, and means for clearing each adding chain and its controlling magnets subsequent to its control of the remaining set of magnets, whereby the totals of the amounts successively entered into the first set of magnets will be progressively represented on the second and third sets of magnets in alternation.

4. In an electrical computing apparatus, a pair of relay adding chains, each comprising two sets of contacts upon which two amounts are settable and interconnected in accordance with the table of addition, means responsive to a single electrical impulse transmitted through the first relay chain for setting one of the sets of contacts of the second chain in accordance with the sum of the two amounts set on the contacts of the first chain, further means responsive to a single electrical impulse transmitted through the second relay chain for setting one of the sets of contacts of the first chain in accordance with the sum of the two amounts set on the contacts of the second chain, means for sending electrical impulses to said chains in alternation, means for clearing the setting in each chain subsequent to its control of the other chain, and means effective intermediate said impulses for setting the other set of contacts of the next chain that is to receive an impulse, in accordance with a further amount.

5. In an electrical computing apparatus, a first and second set of relay contacts, a first set or adding circuit connections controlled thereby, a third set of relay contacts, a second set of adding circuit connections controlled by said first and third sets of relay contacts, means controlled through the first set of adding circuit connections for setting the relay contacts of the third set, means controlled through the second set of adding circuit connections for setting the relay contacts of the second set, means for repeatedly and selectively setting the relay contacts of the first set, sequencing means for rendering the first and second adding circuit connections alternately effective after alternate settings of the first set of contacts, and means for clearing each set of relay contacts subsequent to the control thereby of another set.

WILLIAM LANG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,045,435 Bryce June 23, 1936 2,052,905 Sturm Sept. 1, 1936 2,194,270 Sundstrand Mar. 19, 1940 2,244,241 Bryce June 3, 1941 2,359,616 Bryce Oct. 3, 1944 2,364,540 Luhn Dec. 5, 1944 2,365,381 Boberg Dec. 19, 1944 2,369,430 Brand et al Feb. 13, 1945 2,386,763 William Oct. 16, 1945 

